1. Field of the Invention
This invention relates generally to counterbalanced window operators and more particularly to a counterbalanced operator wherein the counterbalancing force is connected to the arm members and adjustments are able to be made to the counterbalanced mechanism to accommodate various pitches of the roof, weight of the sash and size of the sash.
2. Description of the Prior Art
It is well known in the art to utilize a crank operator for casement type windows. For such windows, the operators have performed satisfactorily. However, when a crank operator has been used for roof or awning windows, various problems have arisen. The first is that due to the weight of the sash, it is necessary that there be a large gear reduction between the crank and the operator mechanism. Typically, it has taken between 25 to 30 revolutions of the hand crank in order to effect a 12 inch (30 cm) movement of the window. Therefore, in order to open a window, it was necessary for a person to make a large number of revolutions of the hand crank. This becomes quite cumbersome for the person operating the mechanism. Furthermore, even with the large gear reduction, the weight of a large roof window sash can cause the cranking torque to be quite high.
Other objects which need to be opened, such as garage doors, are typically counterbalanced in order to allow the person operating the garage door to more easily open and close the garage door. The counterbalancing means are typically located proximate the sides of the garage door. Still further, counterbalancing mechanisms have been utilized in certain windows, but not in the housing of the crank mechanism and not with the counterbalancing forces applied to the same members that open and close the sash from the crank mechanism.
One of the problems which would be encountered in counterbalancing either a roof or awning window would be that the amount of counterbalancing force needed would vary depending upon the pitch of the roof on which the window was placed as well as the size and weight of the sash. With roof windows having arm members attached to the pivoting end of the window, another problem arises from the fact that the pivoting end of the window traces out an arc as the window is opened, but the arm members typically extend linearly. To compensate for the different modes of extension, the joints of the arm members are made relatively loose to provide flexibility.
The present application addresses the problems associated with the prior art devices and provides for a counterbalanced window operator with counterbalance forces on the same members as the crank mechanism. The counterbalancing mechanism may be adjusted to take into account the various roof pitches as well as weight and size of sashes. Still further, the mechanism is designed to match the counterbalancing torque to the torque created by the sash throughout the opening and closing of the window, and the arm members extend in non-linear fashion to better approximate the movement of the pivoting end of the unit.